Abstract: Means are provided for adjustably setting and determining the time duration of flow of a purge gas through process gas supply conduits which supply process gases to semiconductor manufacturing operations. These features are used advantageously to facilitate the changing of certain components of the system, such as a tank of toxic process gas, and/or a filter. A plurality of gas storage and distribution cabinets can be controlled from a single remote personal computer. Alternatively, each individual unit can be controlled by means of its own control system. Setpoints defining, for example, time intervals and pressures to be used in controlling the functions of the gas cabinets may be selected and entered through a front panel on the gas cabinet, or through the remote terminal. A print-out of the selected setpoints is provided by the terminal for improved record keeping of safety procedures used.